Originally posted by iammagi
Now the power light stays off but the fans run and the hard drive light glows constantly. Won't boot up though. Would a dead processor cause the power light to not go on?
Is this after you put a 450w power supply in? Cuz if you haven't put a new power supply in, that would definitely explain something. Try the power supply first. Is the fan in the power supply running (i.e. blowing air out of the computer) properly? Is it making more noise than it used to?
Are you getting any beep codes at all? Hard drive light comes on and doesn't switch off, that means it's getting power. Not getting any instructions though. Suggests that power's not getting through the mobo.
Make sure all the cables from the power supply are connected properly. If the power to the motherboard is P8/P9, make sure that the black wires go next to each other. Everything else is effectively keyed.
Once again, try a new power supply. Probably doesn't matter too much when deciding on a brand. Try to find one with a good warrantee.